1. FIELD OF THE INVENTION
This invention relates to a device for boresighting guns and the like and, more specifically, to a device for boresighting guns for use in conjunction with tanks, though the use thereof in other environments is contemplated.
2. BRIEF DESCRIPTION OF THE PRIOR ART
Current boresighting devices and procedures on armored vehicles are costly, inconvenient and often present situations of extreme peril.
Prior to the use of the presently used Pi-Watson device, boresighting of a gun was accomplished by first taping thread over the end of the gun tube to form a crosshair. The firing pin assembly was then removed from the breech of the gun and the gun loader peered through the gun tube with a pair of binoculars and "talked" the gunner onto a 1200 meter distant target wherein the cross hairs were on the target as viewed through the binoculars. "Zeroing" of the gun was then accomplished by firing a group of three rounds or shots through the target with the gunner then re-aligning the gun sights to the center of the shot group.
Boresighting of U.S. military tank gunsights was improved and is currently accomplished by use of an instrument known as a Pi-Watson device. In order to use this instrument for gun alignment the gun loader of the tank must exit the vehicle and place the Pi-Watson device into the end of the main gun tube. The loader must then be hoisted to the level of the device side eyepiece and look through the side eyepiece into the device. To accomplish this, the loader must generally find something to stand on. While looking through the eyepiece, the loader sees a crosshair and a selected 1200 meter distant target. The 1200 meter target must have a sharp angle for proper alignment of the crosshairs. The loader must then "talk" the gunner onto the target using up, down, left and right commands as in the older art. The gunner then moves the gun according to the commands until the loader advises that the gun is on target. At that time, the loader will have the target in the right lower quadrant on the cross hairs. The loader then removes the Pi-Watson device from the tube, rotates it 180 degrees and places it back into the gun tube. The alignment process is then repeated.
Problems inherent in the Pi-Watson system are that the loader must exit the tank for gun alignment, thereby exposing himself to fire under combat. In addition, the Pi-Watson device is expensive and the procedure required for alignment is long and cumbersome. Furthermore, on occasion, especially due to the exigencies of combat, personnel have forgotten to remove the Pi-Watson device from the gun tube, thereby causing great damage to gun and calibration instrument upon firing the next shot.
It would be desirable from the point of view of a tank commander to have a boresighting tool that could be used with such ease and speed that a boresight performance check can be made on each occasion just prior to entering a battle situation and possibly during lulls in the battle situation itself wherein the inherent dangers to the personnel are minimized.